The present invention relates generally to hypervalent iodine reagents and, more specifically, to a user- and eco-friendly hypervalent iodine reagent, mIBX, and the synthesis thereof.
Hypervalent iodine reagents, due to their low toxicity and ready availability, have attracted considerable attention recently as mild and selective oxidizing agents. Of the various hypervalent iodine reagents known, Dess-Martin periodinane (DMP), and o-iodoxybenzoic acid (IBX) are the most commonly used. Despite the nontoxic nature of these compounds and their ease of preparation, these reagents have certain drawbacks. Both reagents are potentially explosive, and thus cannot be stocked in large quantities. In addition to this drawback, oxidation of alcohols using DMP is carried out in environmentally unsafe chlorinated solvents and reactions employing IBX are often limited in dimethyl sulfoxide (DMSO) due to the reagent's insolubility in other common organic solvents. While oxidation reactions using both DMP and IBX tolerate the presence of moisture in the reaction medium, the presence of large amounts of water, when used as a solvent or co-solvent, is detrimental to the outcome of the oxidation reactions using these reagents. This is due to the fact that the mechanisms of oxidation with both the oxidizing agents involve reactive intermediates formed in an equilibrium step that is disfavored with increasing concentrations of water.
A series of papers from Nicolau Laboratories have recently identified several new oxidative transformations, including a selective oxidation of benzylic carbons using IBX. These reactions were carried out in either DMSO or fluorobenzene/DMSO mixtures. Single electron transfer (SET) reaction pathways have been proposed for these synthetic technologies. A significant aspect of the new oxidative transformations is that the presence of water does not affect the outcome of these reactions. Due to the ever-growing demand for eco-conscious chemical processes, there is a need for a water-soluble derivative of IBX that can behave as a green-oxidant capable of oxidizing alcohols in water. The present invention provides such a derivative, as well as a method of synthesizing the same via a SET mechanism similar to the synthesis of a water-soluble derivative of IBX, referred to herein as modified IBX (mIBX), and oxidation of the allylic and benzylic alcohols using mIBX in water and other eco-friendly solvents.